Electromagnetic motor



Dec. 16, 1947. s, NE r 2,432,600

ELECTED-MAGNETIC MOTOR Filed Sept. 11, 1944 2 Sheets-Sheet l in vezvtors Q5. I. 712 era 6 10 2. 0x761 enseru I ma Dec. 16, 1947. s. E.WERNER ETAL ,60

ELEGTRO-MAGNETIC' MOTOR Filed Sept. 11, 1944 2 Sheets-Sheet 2 69 V 7/ Io o Patented Doc. 16, 1941 ELECTROMAGNETIC MOTOR Sture Eduard Werner andAnders Dalian Jimensen, Stockholm, Sweden, auignora to 'lelefonaktiebolage't L. M. Erlcalon, Stockholm, Sweden, a company of SwedenApplication September 11, 1944, Serial No. 553,628

In Sweden July 9, 1943 Claims. (Cl. 1'l2-36) The present inventionrelates to an electromagnetic motor for operation in two directions ofteletechnical devices, more particularly automatic telephone selectors,by means of electric impulses. The invention relates especially to amotor, in which the rotor turns one angular step at each impulse.

If selectors are used, in which the wipers, upon clearing of acommunication, return to their starting position over the contacts inthe multiple field over which they are set, it is desirable that thedriving device can operate in two directions of motion, the one beingsetting direction and the other restoring direction. Previously, aspring was used as driving device for the restoring, said spring beingset when the driving device steps out the selector. Naturally, therestoring will in that case be quick, but the rapidity of setting willbe counteracted by the resistance of the spring which increases with theincreasing distance of the wipers of the selector from the startingposition. Consequently, the driving devices cannot be entirelyexploited. Moreover, on the wipers returning to starting position a hardshock is produced which may cause disturbances ofother selectors in thesame rack The present invention has for an object a motor for twodirections, eliminating said disadvantage. This is obtained mainly byarranging the motor with two separate stator windings and one centeringdevice for the rotor in such a manner that the rotor is caused to rotatein accordance with the number of impulses in one direction on impulsesbeing sent through one of the statorwindings, and in the other directionon impulses being emitted through the other stator winding. Such amotor-driven selector aflords a soft operation, great rapidity with fulluse of the driving device and, besides, the possibility of stopping thewipers during the restoring operation in other positions than thestarting position.

The invention will be explained more in detail with reference toannexeddrawings.

Figs. 1 and 2 show the principle of two different embodiments of a motoraccording to invention. Figs. 3 and 3a display the principal executionof two motors built together for operation of, for example, a selectorwhich, at the setting, operates in two directions. Figs. 4 and 5 showdifierent switching diagrams for the motor proposed. The drawingscomprise onlydetails necessary for a better understanding of theinvention. a

In the embodiment illustrated by Fig. 1 the rotor is composed of athree-point armature ii.

Said armature is securedv to an armature shaft i2, which is'rnounted onbearings on a yoke 13 'and on parts'of the motor not shown. The motorincludes also among other things two electromagnets l4 and H with thewindings l5 and i2,

respectively, and the pole pieces l6 and I9, respectively. The polepieces are provided with noses and II, respectively, for the operationof the direction of motion of the motor. In'the example shown the middlepoints of the pole pieces are-situated at an angular distance of X95along that part of the circumference of the armature which runs alongthe noses 20, 2|. On the extension of shaft l2 a six-partedsymmetric'stud 22 is provided. Two parallelsides of the stud restagainst a pair of flat springs 23,

the end points of which-being drawn towards each other by means of twosprings 24. Said set of springs which is attached to the rack of themotor by means of devices not shown retains the rotor in the positionshown on de-energization of the motor. Shaft [2- has further a cam disk25 of insulating material with three cams, which at the rotation of theshaft break or close, respectively, the contacts between two pairs ofcontact springs 28, '21 and 28, 29, respectively, which are connected inthe circuits 30 and 3! through the motor windings l5 and i8,respectively.

Fig. 2 shows a modification of the design according to Fig. 1. However,the mechanical centering by means of springs against a sixparted stud inFig. 1 is in this case replaced by a permanent-magnetic centering from apermanent magnet 5|. A winding 54 is rigidly suspended in the rackaround the rotor shaft. This winding is common to the circuits 55 and 58of the two electro-magnets. The electro-magnets are provided with polepieces 51 and 58, respectively, in the same way as the embodimentaccording to Fig. l, and these pole pieces are situ ated at a distanceof 2 70 from each other.

In the following, the operating manner of a motor designed according tothe principles indicated will be described more in detail.

The armature, Fig. l, is retained by the springs 23 in the startingposition as shown. If a close of current takes place in circuit 3ithrough the motor winding I8; a flux is produced throughelectro-magnetfl, pole piece l9, nose 2|, armature'shaft l2 and yoke l3.The armature 1; en turns clockwise one first part-step so that one ofits poles is centered .in front of the pole piece I9. This position ofthe armature is marked with dashed lines in the drawing. Simulassaeootaneously, the springs 22 have been pressed apart by the stud 22 andafter a turning of 90 the stud is placed on edge. Upon turning by afurther degree the spring set tends to press the stud clockwise, but thearmature is retained after a turning of 95 by the flux through the polepiece I9. After interruption of the current in circuit ll there remainsonly the action of the springs 23 upon stud 22. The armature continuesto turn still another part-step (120-95") until springs 23 adherecompletely to the succeeding two plane surfaces on stud 22. The armaturehas then moved a complete angular step of 120.

In the embodiment having a three-parted armature, as shown, the armatureturns 120 by a complete impulse. At each succeeding impulse the armatureturns in the same direction and manner as now described.

On turning of the armature in the direction from the normal positionshown at a close of cir-- cuit 3|, the three-parted cam disk 25 securedto the shaft also turns. Cam disk 25 breaks the contact between thecontact springs 26, 21 as soon as the shaft has moved beyond 90 but lessthan 95. This causes the rotor l2 to proceed automatically about 25 inthe same direction and after that turning the cam of the cam disk havingbroken the contact between springs 26, 21 ceases to mesh with saidsprings, which thus in the starting position of the armature again closethe circuit 3|. Consequently, by means of said cut-offdevice-immediately after close of the circuit 8i--the rotor l2 will beset in continuous rotation.

If circuit 38 is closed instead of circuit 8|, a similar procedure willfollow. The armature ll turns counter-clockwise until one of its poleshas come opposite pole piece i6, that is, an angular movement after thecircumference of armature of 95. It proceeds after the break of thecurrent to the neutral position under the action produced by thepressure of springs 23 against the six-parted stud 22. If theself-interruptor actuated by cam disk 25 is connected to circuit 88,armature ll starts a continuous rotative movement counter-clockwise. Ifsaid cut-off device is disconnected from circuit 88, 3|, respectively,the armature moves one angular step at each impulse in this circuit. Theembodiment according to Fig. 1 thus shows an impulse motor, wherein thesame armature by means of only two circuits may be driven in twodirections of motion, and in both directions in case of self-operationand step-bystep operation.

The embodiment described includes a six-parted stud 22. Should instead athree-parted stud be used and a fiat spring which presses against asurface of the three-parted stud in the same way as the upper spring 23,Fig. 1, the middle points of the pole pieces may be placed at an angulardistance from each other of about 2X70. In such a case the stud has thetip placed against the spring after 60. n the stud being moved furtherto 70 the armature is pressed clockwise by the action of the springagainst the stud. When the flux through the pole piece ceases, the

rotor therefore continues to turn another part-.

step (120-70). The cam disk will in that case break the contact betweensprings 28 as soon as the shaft has turned somewhat more than 60, butless than 70, in which case an identical operating manner as above isobtained. I

The embodiment according to Fig. 2 has chiefly the same operating manneras described above. The armature is centered in the neutral position bythe flow from the permanent magnet II. at

a close of the current in circuit II, a iield is produced in coil 54opposing the permanent field in shaft 82, causing the liberation of thearmature from the centering. The pole piece I! is magnetized, wherebythe armature turns towards said somewhat but is drawn back by thepermanent field, swings out quickly and stops in neutral position.

Fig. 3 illustrates how two motors according to Fig. 2 are builttogether. 8| and I2 designate the armatures of the two motors, 83 and 88being electro-magnets, and l and 88 permanent magnets, the flows of whiare closed through the armatures 8i and 82 as well as through the shaftsof the armatures and a yoke not shown. The shafts of the armatures 8|and 82 are encircled by the fixed windings I1, 88 in relation to therack. Two self-interruptors are comprised in the motor, one for eachdirection of motion. Said self-interruptors being common to both motorsare shown in Fig. 3a, 18 and I4 designating cam disks of insulatingmaterial on the armature shafts for armatures ii and 82, respectively.Further, there is a self-interruptor 88, 18 so arranged that it isactuated when cam disk 18 turns counter-clockwise and cam disk H turnsclockwise. Another self-interruptor, also containing two contact springsH, 12, is arranged to be actuated in case of reverse direction of motionof the two cam disks II, II. A double motor of similar design isdescribed more in detail in the U. S. patent application Serial No.522,668, now Patent Number 2,404,332, July 16, 1946. The operation ofthe motor in Figs. 3 and 3a according to the present application will bedescribed with reference to Fig. 5.

Fig. 4 shows the principle of a switching diagram relating to a motoraccording to'Fig. 2,

which is presumed to be used as driving device for a final selector inan automatic telephone installation. windings 82 and 84 correspond towindings I5 and '51, respectively, in Fig. 2 and winding 88 correspondsto winding 54. It now current impulses are emitted through windings 82,88 from an impulse emitter, for example, dial 8! at a subscriber, therotor will turn step by step according to the impulses in one direction,for example counter-clockwise. In known manner, the wipers of theappropriate selector are moved in one direction, for example from thenormal position. If now the rotor is caused to move in the otherdirection, the wipers of the selector will in the ordinary way bestepped forward in the reverse direction, that is, back to normalposition. With the switching diagram according to Fig. 4 this isachieved by connecting windings 81, 84

' to a circuit over contacts 88 and 88 and a selfbreaking contact 85.Said contact 85 corresponds, as is the case with contact 81 for exampieto the self-breaking contact 28, 28 and 28, 21, respectively, in Fig. 1,and it is actuated by a cam disk in the same manner as described withreference to Fig, 1. Contact 88 is presumed to be a contact of a knownexecution which is broken in the starting position of the selector arms.The return movement of the selector is started in the ordinary way bymeans of a relay 88, when said relay closes its contact 89, and isinterrupted at the break of contact 86. Said break by means of contact86 should take'place during the latter part of an'angular step, that iswhen windings 84, 83 are de-energized.

Fig. 5 displays the principle of a group selector in connection withautomatic telephone installations, which at its'setting operates in twodirections, X and Y. The motor according to Fig. 3 is assumed to be thedriving device of the selector. Windings 9| and 92 carrespond towindings 61 and 68, respectively, and windings 93 and 94 correspond toelectro-magnets 03 and 64, respectively. Details 9'! and 98 correspondto the shafts supporting the armatures GI and 62, respectively. Bothshafts have common self-interruptors according to Fig. 3a and these havein Fig. 5 been designated 95 and 96, respectively. 95 acts asself-interruptor, when any of the shafts sets its devices, and 96, whenthe shafts restore the corresponding devices. The figure iurther shows aholding relay 99 with contacts I00, IOI, I02, an impulse emission relayI03 which is slow-acting in release and provided with contacts I04 andI05, as well as a listening relay I06 with contacts I01 and I08, thelatter of which being connected in parallel: with a resistance. Theselector wipers are termed a, b, c and d, and the home position contactsof the selector in the X-movement and Y-movement, respectively, aredesignated I2I, I22, respectively; I23, I24. Uppermost, to the left, thesubscribers dial I09 is indicated.

One energizatiomin known manner, of relay 99 an impulse circuit isprepared over details I02, 95, 93, 92, I23 and dial I09. When an impulsetrain is emitted by the dial, relay I03 operates and remains in operatedposition during the entire train, in known manner. Contact I04 is brokenand contact I05 closed, preventing the selector from entering intoself-operation during the impulse train. The impulses now pass overcontact I05 instead of interrupter 95. One rotor (X-rotor) follows theimpulses of the dial and sets the wipers in the X-movement. When theimpulse train is terminated, relay I03 is demagnetized, winding 9ithereby becoming energized over contact I04. At the same time followsremoval of the short-circuit caused by self -interrupter 95 by means ofcontact I05. The other rotor (the Y-rotor) now enters intoself-operation in a circuit over details IOI, I04, I01, I22, 9I, 93, 95and I02, setting the wipers in the Y-movement. When the c-wiper of theselector finds a free wire in the multiple of the selector, a circuit isclosed over the c-wire and relay I06'to contact I00. Listening relay Iis actuated and breaks, by means of contact I01, said circuit. Saidoperation takes place during that part of the second impulse step, whenthe motor is de-energized. The rotor stops, whereupon the call isestablished in the ordinary way. On termination of the conversation, theholding relay 99 is released in known manner.

The Y-rotor is now set rotating in the other direction in acircuit I02,96, 94, 9|, I24, IN, and drives the wipers back in the Y-direction.After completion of this return, contact I24 is reversed and the X-rotoris driven in a direction reverse to the previous one in a circuit IOI,I24, I2l, 92,

94, 96, I02. In the home position contact I2I is broken and the rotorstops.

The principle of the invention may of course be applied to otherembodiments than those displayed in the drawing. The number of poles maybe arbitrary. The yoke mentioned may be replaced by armature and polepieces arranged as those shown, causing the moment of the motor to benearly redoubled at an equal dimensioning of the motor.

The field of application of the motor may be increased by letting theleakage fluxes of the electro-mag'nets I4 and H, Fig, 1, actuate springgroifns over some simple armature construction.

Should, for example, core I4 project beyond pole piece I6 and theprojecting part of the core be split lengthwise and one of the parts beencircled by a copper ring, a relay slow-acting in release is affordedwhich may be used for other switchings from the motor, for example forindication of restoring. a

We claim:

1. In an electric motor, a step-wise movable rotor, two separate motorwindings, means for periodically energizing one of said windings toinitiate a step-wise movement of the rotor in one direction, means forperiodically energizing the other winding to initiate a step-wisemovement of the rotor in the opposite direction, and common meanseffective during movement of the rotor in either direction to completethe stepwise movement and center the rotor in position prior toinitiation of. the next step-wise movement.

2. A motor as claimed in claim 1 wherein said common means isconstituted by a permanent magnet.

3. A motor as claimed in claim 1 wherein said common means isconstituted by a cam and spring means coacting with said cam.

4. A motor as claimed in claim 1 provided with pole pieces supportingsaid windings, noses coacting with said rotor and projecting in oppositedirections from the pole pieces, said common means being constituted bya permanent magnet. 5. A motor as claimed in claim 1 provided with polepieces supporting said windings, noses coacting with said rotor andprojecting in opposite directions from the pole pieces, said commonmeans being constituted by a cam and spring means coacting with saidcam. STURE EDUARD WERNER.

ANDERS OSSIAN JORGENSEN.

REFERENCES CITED" The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Muller et al. May 28, 1935

